Paris is regarded as the "Museum City". While there is the world- renowned Louvre where just about every masterpiece is housed, there are other museums that also house the more unusual side of the city.

Collections of erotica, an underground home to skulls and more, here are some of the quirky museums of Paris travelers should add to their itinerary.

1. Musée de l'Erotisme

Erotic art can easily stir or disturb anyone. As for travelers who are on the more adventurous side, Musée de l'Erotisme managed to pack seven floors filled with erotica thanks to avid collectors Alain Plumey and Joseph Khalifa. From the history of Parisian brothels, phallic symbols of Peruvian pottery as well as fertility symbols and the more modern erotic art, guests are bathe in everything that celebrates the sexual human body.

2. Les Catacombes de Paris

One of the most famous museums in Paris, Les Catacombes de Paris welcomes everyone with a sign on its entrance saying, "Arrête! C'est ici l'empire de la mort" which translates to: "Stop! This is the empire of death".

With millions of human skulls and bones lined up for guests to see, this catacomb is more than just bones. Apart from its history being an underground burial for the dead who could not afford a spot in the cemetery, the place is also a geological journey of how limestone was deposited at the time.

3. Musée Edith Piaf

Believed to be the greatest Parisian singer who ever lived, Edith Piaf left a mark in the music industry of Paris. So much so that an entire museum is dedicated to her.

Musée Edith Piaf houses found objects, pictures, letters, framed discs and more, all belonging to the singer. While the museum is quite small, the charm of the place can easily capture anyone, adding to the fact that the curator only speaks French.

4. Le Musée des Égouts de Paris

Apart from the skulls, erotica and all that is Edith Piaf, Paris is also home to possibly the world's most unusual museum, Le Musée des Égouts de Paris or the Museum of Sewers.

Guests will not experience swimming through the city sewers but they are given a walking tour of the extensive sewers of Paris, showcasing both the non-drinking and drinking water passages of the city. These sewers are so popular that they are also written about in the iconic piece, Les Misérables.